An immersed boundary-material point method for shock-structure interaction and dynamic fracture

Abstract

As a class of extreme fluid-structure interaction (FSI), shock-structure interaction problems are always accompanied with dynamic fracture phenomena in solid structure. During the dynamic fracture process, small fragments of thin geometry and fresh FSI interfaces will be generated, which makes the FSI interface difficult to be reconstructed. An immersed boundary-material point method (IBMPM) is proposed in this paper for simultaneous simulations of shock-structure interaction and accompanied dynamic fracture. The finite volume method (FVM) is employed as fluid solver and specifically a TVD Riemann solver is adopted for shock simulation, while the material point method (MPM) is employed as solid solver for simulation of extreme deformation problem. The FVM and MPM are then coupled by our improved immersed boundary method (IBM) which is named as Lagrangian continuous-forcing IBM (lg-CFIBM). The lg-CFIBM is proposed in the frame of continuous forcing approach with a compact support area for the immersed boundary conditions. It can guarantee the boundary velocity conditions strictly at each time step and has no need to reconstruct FSI interfaces. Several numerical examples, including shock-cylinder obstacle interaction, flexible panel deformation induced by shock wave and fragmentation driven by detonation, are studied to verify and validate the proposed method, and numerical results are in good agreement with experiments.